The invention is of particular interest for lighting systems which cover a large area, for example road lighting networks.
FIG. 1 shows a typical lighting control system, and shows the topology of the control network. The network has a local controller in a cabinet 10 which controls all the control nodes (i.e. lighting units) 16 along a cable. The local controller communicates with the back end 12. The locations of the cables and cabinets are known and there is a correspondence between the physical configuration and the control topology. Thus, once the central controller 10 has been commissioned, the assets (cabinets and cables) can be easily commissioned and managed.
FIG. 2 shows how an individual lighting system is controlled. There is no local controller in a cabinet. Instead, each node (i.e. light unit) has an individual controller, and they are under the control of one or several central controllers 12. The power is nevertheless delivered from an associated cabinet and cables extending from the cabinet. In the system of FIG. 2, it is not known where the cabinet is, nor is the cable path known. From a network point of view, all that can be observed at the central controller 12 is the number of discrete nodes.
Lighting control systems are evolving towards individual control systems as shown in FIG. 2.
For the individual lighting control system of FIG. 2, there may in fact be a few central controllers, but equally there may be only one controller, even for thousands of lighting units 16 (each of which can be considered as a separate control node). The network topology is no longer dictated by a fixed power cable arrangement associated with each cabinet 10 as in the example of FIG. 1.
Thus, the cable and cabinet information is not available in straightforward manner to the back end 12. The back end for example only has information relating to the individual lighting units, and all of the lighting units are identified as discrete points. The back end does not have knowledge of how the lighting units are physically connected, for example the cable routes between lighting units, or the locations of cabinets which control strings of lighting units.
The end users, for example road lighting bureaus, nevertheless have a responsibility to maintain these non-lighting assets, and ensure their correct functioning. To provide the end user with knowledge of the cable and cabinet locations and configurations, it becomes necessary for the system commissioner to cross-check the street construction design, and add cable and cabinet asset information manually.
There is a need to provide automated collection and management of these assets of a lighting system.
WO 2014/033558 discloses a system which uses voltage measurement to determine the location of luminaires along a track, for commissioning purposes. However, this method assumes that the location of the track is itself known and the purpose is to find the position of the luminaires within the known grid.